Device for feeding wrapper sheets, especially for use in cigarette packing machines

Abstract: Device for feeding sheets of, for example, foil, especially for use in cigarette packing machines, with a drum (7) having cells (2') in which the sheets (8) are folded around individual groups (3) of cigarettes (S) as each group (3) of cigarettes (S) is transferred from a transfer drum (1) having cells (2) to said folding drum (7) at a transfer point (T) where the cigarette-carrying cells (2, 2') of the two drums (1, 7) coincide face to face and to where the sheet (8) is fed in a predetermined position with respect to the group (3) of cigarettes (S) and between the cells (2, 2') of the two drums (1, 7) by pick-up/positioning means (14, 114) associated with the transfer drum (1). According to the invention the sheet (8) pick-up/positioning means consist of a separate pick-up/positioning drum (14, 114) supported coaxially with the transfer drum (1) and rotated (21) independently of it.

Description: The invention relates to a device for feeding wrapper sheets, especially for use in cigarette packing machines, which device comprises a drum in which the sheets of, for example, foil are folded around individual groups of cigarettes, said drum being provided around its periphery with a plurality of cigarette-carrying cells, and a drum which transfers groups of cigarettes from a feed line to the folding drum which is likewise provided with at least one cigarette-carrying cell, said cell being carried to a transfer point in a coinciding position of alignment in front of an empty cigarette-carrying cell in the folding drum, while the group of cigarettes is moved by displacement means out of the cell of the transfer drum into the cell of the folding drum, the transfer drum being associated with means which pick up and position one sheet at a time in a predetermined position next to the group of cigarettes being transferred, between the transfer drum cell and the folding drum cell at the transfer point, so that as the group of cigarettes is transferred into the folding drum cell, the sheet is pushed by the cigarettes themselves into said cell and folded around them in a U shape. A device of this type is known from DE-A-37 31 063: here, the foil sheet pick-up/positioning means are carried by the transfer drum itself, rotating with it alongside each cigarette-carrying cell of said drum. The sheets must therefore be picked up by the transfer drum itself, already in the correct predetermined position with respect to the corresponding cigarette-carrying cell, as no means are provided to enable its position relative to said cell to be adjusted. Moreover, the transfer drum has only two diametrically opposite cigarette-carrying cells which are moved alternately and simultaneously, in a half-rotation of the drum, firstly to a cigarette group feed point, where the feed line arrives, and secondly to the point of transfer to the folding drum. The known device is consequently unable to increase the speed of rotation of the transfer drum above a certain limit, owing to the fact that at very high speeds accurate picking-up and positioning of the sheet can no longer be guaranteed. This drawback necessarily means that sheets not correctly positioned must be discarded, or else a defectively made pack must be discarded later. This fact and the fact that only two cigarette-carrying cells are provided are the reason for the undesirable limiting of operating speeds and hence of hourly output. The invention is accordingly based on the problem of how to construct a device for feeding wrapper sheets of, for example, foil, especially for use in cigarette packing machines, which by means of a simple and relatively inexpensive design enables these drawbacks to be overcome and so guarantees a higher hourly output and correct operation even at higher operating speeds. The invention solves the above problem with a device for feeding sheets, especially for use in cigarette packing machines, in which the sheet pick-up/positioning means consist of a separate pick-up/positioning drum supported coaxially with the transfer drum and rotated independently of it. This approach not only simplifies the construction of the transfer drum and of the pick-up/positioning means, but also makes it possible continuously to adjust the position of the sheet with respect to the corresponding cigarette-carrying cell of the transfer drum at the transfer point. Another feature is that the pick-up/positioning drum consists of two discs arranged against the sides of the transfer drum, coaxially with each other and with said transfer drum and coupled to each other in rotation. The transfer drum has two or more cigarette-carrying cells, while the pick-up/positioning drum is provided with peripheral sheet-placing sectors in any number, preferably more or less than the number of cigarette-carrying cells of the transfer drum, the pick-up/positioning drum being operated relatively to said transfer drum in such a way that one sheet is brought simultaneously with each cigarette-carrying cell, and in the correct position, to the transfer point. The transfer drum and the folding drum are turned stepwise and pause at at least the transfer point, while the pause at the transfer point of the pick-up/positioning drum, with the sheet in the correct predetermined position relative to the cigarette-carrying cell, is controlled by stationary sensors sensitive to the position and optionally to the presence of the sheet which turn on or off a motor driving the pick-up/positioning drum. In this way the sheet can always be positioned in the correct relative position with respect to the associated group of cigarettes, and as a result the influence of synchronization errors, imprecisions in the rotary motion of the transfer drum and pick-up/positioning drum and errors in the position in which the sheet is picked up by the corresponding sheet-placing sector, are eliminated. The sheet-placing sectors advantageously work by suction. They consist of axially adjacent pairs of suction areas in the peripheral edges of the discs forming the pick-up/positioning drum. Said sectors extend to a radial distance from the axis of rotation which is slightly greater than the external diameter of the transfer drum and are at least approximately equal in length to the sheet, or preferably slightly longer. Their axial distance apart is less than the dimension, in the axial direction, of the sheets. The sheet-placing sectors are preferably carried by basically radial arms rigidly connected together by a common hub. The invention also encompasses other features which further improve the above wrapper sheet feeding device and are the subject matter of the dependent claims. The distinctive features of the invention and its resulting advantages will appear in greater detail in a description of a preferred embodiment, which is illustrated as a non-limiting example in the accompanying drawings, in which: Fig. 1 is a schematic front view of a feeder device according to the invention, and Fig. 2 is an axial section on a larger scale of the details of the transfer drum and associated pick-up/positioning drum shown in Fig. 1. With reference to Fig. 1, a device for feeding sheets of foil in a cigarette packing machine comprises a transfer drum 1 supported so as to rotate about its axis. The transfer drum 1 rotates preferably stepwise, and around its periphery are a plurality of cigarette-carrying cells 2, in particular four cigarette-carrying cells 2, distributed at equal intervals and open on the peripheral surface of the drum. The cigarette-carrying cells 2 are intended to hold a group 3 of cigarettes S already arranged in the predetermined arrangement which the cigarettes S are to assume in the finished packet. The cells are oriented such that the longer transverse side of the group of cigarettes 3 lies in the radial direction of the transfer drum 1. The transfer drum 1 has the function of carrying said ordered groups 3 of cigarettes S from a pick-up point P to a transfer point T where the group of cigarettes 3 is transferred to a coinciding empty peripheral cell 2' of a folding drum 7 which likewise has cells. The folding drum 7 is also turned stepwise about an axis parallel to that of the transfer drum 1 and is aligned therewith. The groups of cigarettes 3 are preformed upstream of the transfer drum 1 and are fed into the pick-up point P by means of, for example, tubular conveying cradles 4 mounted side by side on an endless conveyor belt 6. At the pick-up point P the cells 2 of the transfer drum 1 are brought one by one to a position that coincides axially with the respective tubular cradle 4 and the corresponding group 3 of cigarettes is passed into the cigarette-carrying cell 2 in an axial translational displacement of the cigarettes S by means of a pusher or the like (not shown). The position of the transfer point T relative to the pick-up point P is such that whenever an empty cigarette-carrying cell 2 is at the pick-up point P, a loaded cigarette-carrying cell 2 is simultaneously at the transfer point T in a position coinciding face to face with an empty cigarette-carrying cell 2' of the folding drum 7. There is fed in at the transfer point T, next to each cigarette-carrying cell 2 and in a predetermined position with respect to said cell, between said cigarette-carrying cell 2 of the transfer drum 1 and the empty cigarette-carrying cell 2' of the folding drum 7, a sheet of foil 8. The transfer of the group of cigarettes 3 from the cigarette-carrying cell 2 to the coinciding cell 2' of the folding drum 7 is accomplished by means of the translation of the group of cigarettes 3 in a radial direction transversely to the axis of the cigarettes S. In Fig. 1 the displacement means are depicted schematically by a pusher 9. At the same time the group of cigarettes 3 pulls the sheet of foil 8 into the cell 2', thereby folding it into a U shape as indicated by 8' in Fig. 1. Each cigarette-carrying cell 2' of the folding drum 7 is then moved to a plurality of successive folding locations where other folding means (not shown) fold the projecting flaps of the sheet 8' (already folded into a U shape) so as to enclose the corresponding group of cigarettes 3. The sheets of foil 8 are cut from a web of foil 8'' by means of a rotating blade forming part of a feeding and cutting unit indicated as a whole by the reference 10 and comprising at least two pairs of opposing powered feeder rollers 110, 210. The feeding and cutting unit 10 is preferably situated underneath the transfer drum so that the web of foil 8'' or at least the cut sheet 8 is fed vertically with it. With reference to Fig. 2, the transfer drum 1 is mounted on and rotates with a projecting shaft 11 supported rotatably in the frame 12 and turned stepwise by a motor through an intermittent transmission 13 or "rotoblock". In the example illustrated the transmission 13 consists of a two-dimensional cam 113 in which rollers 111 mounted on the ends of radial rods 211 projecting from the shaft 11 engage. The sheet of foil 8 cut from the web 8'' is picked up and carried into the correct predetermined position at the transfer point T by means of a pick-up/positioning drum. The sheet 8 pick-up/positioning drum consists of two discs 14 positioned coaxially with each other and with respect to the transfer drum 1 on both sides of the latter. The discs 14 are coupled so as to rotate with each other and with respect to the shaft 11 of the transfer drum 1, each by means of its own hub 15 which rotates on bearings 16 about the shaft 11 on the corresponding side of the transfer drum 1. Each hub 15 is coupled in rotation to a coaxial pulley, or in particular a toothed wheel 17 made e.g. in one piece therewith, around which runs a belt, in particular a toothed belt 18, that is turned by a driven pulley or sprocket 19. The sprockets 19 are fixed to and rotate with a common shaft 20 of a common independent motor 21. The motor 21 is supported in the frame 12 and its shaft 20 projects from it. Furthermore the free end of the shaft 20 is also supported rotatably in a bracket 23 in which the free end of the shaft 11 of the transfer drum 1 is also held. The discs 14 comprise around their periphery a predetermined identical number of sheet-placing sectors 114 operating by suction. These are distributed at equal angles and coincide with each other in pairs. The sheet-placing sectors 114 are formed by peripheral segments of the discs 14 that project a short radial distance beyond the peripheral edge of the transfer drum 1. Emerging around their edges are suction ducts 214 formed in the thickness of the discs 14 and connected by suction ducts 115 inside the hubs 15 with an external suction source (not shown) with the aid of airtight rotating connections shown schematically and indicated by the reference 22. The sheet-placing sectors 114 are slightly longer than the sheets of foil 8 and their axial distance apart is less than the dimension in the axial direction of these sheets of foil 8. In order to reduce the inertial mass of the pick-up/positioning drum, the sheet-placing segments 114 are advantageously supported by arms 314. In this case, the suction ducts 114 are formed in said arms 314. The arms 314 may consist, as shown, of circular sectors of the discs 14. As each pair of adjacent suction segments of the discs 14 passes the foil sheet 8 feeding and cutting unit 10, the corresponding sheet 8 is picked up by suction by said pair of suction segments which then carry it to the transfer point T, positioning it correctly with respect to the cigarette-carrying cell 2 of the transfer drum 1. The movement of the pick-up/positioning drum is independent of that of the transfer drum 1 and said pick-up/positioning drum is made to pause once the sheet 8 is in its correct position on the command of a pair of sensors 24 which detect the position and presence of this sheet 8. Said sensors 24 may be a pair of sensors arranged side by side in the direction of rotation and may be of any type, for example one to emit a light barrier and the other to receive it, and suchlike. With reference to Fig. 1, in the example illustrated, the number (in particular three) of sheet-placing sectors 114 on the pick-up/positioning drum is less than the number of cigarette-carrying cells 2 on the transfer drum 1. The transfer drum 1 and the pick-up/positioning drum are therefore driven independently at relative speeds such that at the transfer point T the presence of each loaded cigarette-carrying cell 2 of the transfer drum 1 coincides more or less with the presence of a sheet of foil 8. Because of the independent drive to the pick-up/positioning drum, and because of the position sensors 24, the sheet 8 can always be positioned accurately relative to the cells 2, 2' of the two drums 1 and 7, independently of operating speeds. The invention is obviously not limited to the embodiments described above and illustrated and may be greatly varied and modified, especially from the structural point of view. In fact, the feeder device according to the invention is not limited to the use illustrated in the example, but can also be used for feeding and positioning wrapper sheets of any type and dimensions in packaging machines for similar or other kinds of products. With particular reference to cigarette packing machines, the device according to the invention can also be used in much the same way both for the feeding and correct positioning of external packaging sheets for making so-called soft packets, in which each group of cigarettes, optionally already enclosed in the foil sheet, is wrapped in an extra wrapping sheet of paper, and for the feeding and correct positioning of cardboard blanks and the like for making so-called rigid packets. None of these variants would constitute a departure from the underlying principle described above and claimed below.

Claims: Device for feeding wrapper sheets, especially for use in cigarette packing machines, which device comprises a drum (7) in which the wrapper sheets of, for example, foil are folded around individual groups (3) of cigarettes (S), said drum being provided around its periphery with a plurality of cigarette-carrying cells (2'), and a drum (1) which transfers groups (3) of cigarettes (S) from a feed line (4,6) to the folding drum (7) which is likewise provided with at least one cigarette-carrying cell (2), said cell being carried to a transfer point (T) in a coinciding position of alignment in front of an empty cigarette-carrying cell (2') in the folding drum (7), while the group (3) of cigarettes (S) is moved by displacement means (9) out of the cell (2) of the transfer drum (1) into the cell (2') of the folding drum (7), the transfer drum (1) being associated with means (14, 114) which pick up and position one sheet (8) at a time in a predetermined position next to the group (3) of cigarettes (S) being transferred, between the transfer drum (1) cell (2) and the folding drum (7) cell (2') at the transfer point (T), so that as the group (3) of cigarettes (S) is transferred into the folding drum (7) cell (2'), the sheet (8) is pushed by the cigarettes (S) themselves into said cell (2') and folded around them in a U shape (8'), characterized by a sheet (8) pick-up/positioning drum (14, 114) supported coaxially with the transfer drum (1) and rotated (21) independently of it. Device according to Claim 1, characterized in that the pick-up/positioning drum consists of two discs (14) arranged against the sides of the transfer drum (1), coaxially with each other and with said transfer drum (1), coupled to each other in rotation and rotating relative to the transfer drum (1). Device according to either of Claims 1 and 2, characterized in that the transfer drum (1) has two or more cigarette-carrying cells(2), while the pick-up/positioning drum (14) is provided with peripheral sheet-placing sectors (114) in any number, preferably more or less than the number of cigarette-carrying cells (2) of the transfer drum (1), the pick-up/positioning drum (14) being operated (21) relatively to said transfer drum (1) in such a way that one sheet (8) is brought simultaneously with each cigarette-carrying cell (2), and in the correct position, to the transfer point (T). Device according to one or more of the previous claims, characterized in that the folding drum (7) and the transfer drum (1) are turned (13) stepwise, pausing at at least the transfer point (T), while the pause at the transfer point (T) of the pick-up/positioning drum (14), with the sheet (8) in the correct predetermined position relative to the cigarette-carrying cell (2) is controlled by stationary sensors (24) sensitive to the position and optionally to the presence of the sheet (8) which turn on or off an independent motor (21) driving the pick-up/positioning drum (14). Device according to one or more of the previous claims, characterized in that the sheet-placing sectors (114) work by suction. Device according to one or more of the preceding claims, characterized in that the sheet-placing sectors (114) consist of suction areas in the peripheral edges of the discs (14) forming the pick-up/positioning drum and said suction areas of the two discs (14) are aligned adjacently in pairs. Device according to Claim 6, characterized in that the sheet-placing sectors (114) extend to a radial distance from the common axis of rotation of the transfer drum (1) and discs (14) which is slightly greater than the external radius of this transfer drum (1) and are at least approximately equal in length to the sheet (8), or preferably slightly longer. Device according to Claim 6 or 7, characterized in that the axial distance between the adjacent sheet-placing sectors (114) is less than the dimension, in the axial direction, of the sheets (8). Device according to one or more of Claims 6 to 8, characterized in that the sheet-placing sectors (114) of each disc (14) are carried by basically radial arms (314) rigidly connected together by a common hub (15). Device according to Claim 9, characterized in that the sheet-placing sectors (114) consist of the peripheral edge of equiangularly distributed circular sectors (314) of the discs (14) forming the pick-up/positioning drum. Device according to one or more of Claims 6 to 10, characterized in that emerging around the peripheral edges of the discs (14) forming the sheet-placing sectors (114) are suction ducts (214) formed radially in the thickness of the arms (314) and connected by ducts (115) inside the hubs (15) of the discs (14) to a suction source by means of mobile airtight connections (22). Device according to one or more of the previous claims, characterized in that the discs (14) of the pick-up/positioning drum are supported (15, 16) so as to rotate freely and independently of each other on the driveshaft (11) of the transfer drum (1), being driven by a common shaft (20) belonging to a single drive motor (21) to which they are each connected dynamically by means of an independent transmission. Device according to Claim 12, characterized in that the hub (15) of each disc (14) is coupled in rotation to, and preferably made in one piece with, a coaxial pulley or toothed wheel (17) connected to an associated pulley or to an associated sprocket (19) by means of a plain or toothed belt (18), said sprockets (19) being fixed to a single shaft (20) which is parallel with the axis of rotation of the discs (14), is driven by a motor (21) and projects from it. Device according to one or more of the previous claims, characterized in that it includes a cutting and feeding unit (10) which cuts sheets (8) from a continuous web (8') and feeds the sheets to the pick-up/positioning drum in vertical alignment therewith and in a predetermined orientation correlated to its position at the transfer point (T). Device according to one or more of the previous claims, characterized in that the drive shaft (11) of the transfer drum (1) projects from the latter and is parallel with the drive shaft of the pick-up/positioning drum (14), both said shafts being supported in such a way as to allow free rotation in a common member (23) connecting their free ends.

Inventors: SPADA VALTER, TOSI GIUSEPPE, SPADA, VALTER, TOSI, GIUSEPPE
Applicants: SASIB SPA, SASIB S.P.A.
Application year: 1994
Main classification: B65B19
IPC codes: B65B19